BTE-Barna: An extension of almaBTE for thermal simulation of devices based on 2D materials

We present BTE-Barna (Boltzmann Transport Equation - Beyond the RTA for NAnosystems), a software package that extends the Monte Carlo (MC) module of the almaBTE solver of the Peierls-Boltzmann transport equation for phonons (PBTE) to work with nanosystems based on 2D materials with complex geometries. To properly capture how the phonon occupations evolve in momentum space as a result of scattering, we have supplemented the relaxation-time approximation with an implementation of the propagator for the full linearized version of the PBTE. The code can now find solutions for finite and extended devices under the effect of a thermal gradient, with isothermal reservoirs or with an arbitrary initial temperature distribution in space and time, writing out the temperature and heat flux distributions as well as their spectral decompositions. Besides the full deviational MC solver, a number of useful approximations for highly symmetric devices are also included.

本报告介绍了一种名为BTE-Barna（玻尔兹曼传输方程——超越RTA用于纳米系统）的软件包，该软件包扩展了基于Peierls-Boltzmann传输方程（PBTE）的声子解算器almaBTE的蒙特卡罗（MC）模块，使其能够与基于复杂几何形状的二维材料纳米系统协同工作。为了准确捕捉声子占据在动量空间中的演化过程，我们补充了弛豫时间近似，并实现了PBTE全线性化版本的传播子。现在，该代码能够在热梯度作用下，针对有限和扩展设备求解解，支持等温储热器或任意初始时空温度分布，并输出温度和热通量分布及其光谱分解。除了完整的偏差蒙特卡罗求解器外，还包含了一系列适用于高度对称设备的实用近似方法。